The civil aviation regulator DGCA has asked budget carriers IndiGo and GoAir to carry out changes in15 of the engines manufactured by US aerospace company Pratt & Whitney mounted on their aircraft. The replacements will have to be carried out on six of IndiGo\u2019s aircraft and one aircraft of GoAir. The directive of the DGCA (Directorate General of Civil Aviation) follows two Air worthiness Directives (ADs) issued by the American aviation watchdog the Federal Aviation Authority (FAA) on November 7. The directive seeks replacement of high pressure compressor or HPC front hub that wears due to corrosion issues, according to FAA. The US watchdog mandates that these changes be affected within 120 days after effective date that is December 12, 2018 or if the engines have exceeded 6,180 cycles or within five years since the ship date as indicated the AD, whichever occurs first. \u201cSome of the engines installed on aircraft operated by Indian operators are affected. Indian operators have sufficient time to become compliant,\u201d a senior DGCA official said, adding that the ADs are \u201cmandatory\u201d and directed the Indian operators to comply within the period as indicated in the directives. Both GoAir and IndiGo that have Pratt & Whitney engines PW1100 from series 450 to 614 mounted on their Airbus A320Neos have been grappling with engine woes for over six months now with aircraft being grounded due to these issues. Both the carriers have 82 of the affected aircraft in their fleet. Another FAA directive also requires these airlines to replace certain parts on the mentioned engine series to address failure of knife edge seal issues. \u201cBoth IndiGo and GoAir are compliant on the same,\u201d the DGCA said.